Evolution of interface and mechanical performance of Cu-xAl/1010 steel bimetal laminated composite

Abstract

Composited with steel is a commonly used method to improve the strength and toughness of bearing materials. The Cu-x wt% Al/1010 steel (x = 0, 6, 7.5 and 9) bimetal laminated composites (BLCs) were fabricated by continuous solid/liquid bonding, and four well bonded and interface defect-free BLCs were obtained. The interfacial microstructure evolution and bonding mechanism were investigated in Cu-xAl/1010 steel BLCs with different Al contents. The results show that a straight metallurgically bonded interface is formed in pure Cu/1010 steel BLC, and a diffusion layer composed of Fe and Al appears on the side of the 1010 steel in Cu-7.5Al (C61000)/1010 and Cu-9Al (C61800)/1010 steel BLCs. In contrast, a transition layer of Cu-Al-Fe is formed in Cu-6Al (C60800)/1010 BLC due to the grain boundary diffusion. The tensile-shear test results show that the interfaces are always well bonded and fracture occurs on the Cu-xAl side after large deformation. The formation of this sufficiently strong interface is attributed to the diffusion layers and tight interatomic bonding between Cu and Fe. The tribology properties of the three Cu-Al alloys (C60800, C61000 and C61800) under different speed and load were also revealed. It is substantiated that the wear resistance increases with increasing the content of Al, and the wear mechanism changes from adhesive wear to abrasive wear due to the formation of β'-AlCu3 phase. The results provide significant guidance for industrial preparation of bimetal laminated composites involving Al and Fe, and a necessary consideration for the study of lead-free bearing of Cu-Al alloy.